Subject: [PATCH] Fix CVE-2017-12836
From: Thorsten Glaser <tg@mirbsd.de>

--- cvs-1.12.13+real/src/rsh-client.c
+++ cvs-1.12.13+real/src/rsh-client.c
@@ -53,7 +53,8 @@
     char *cvs_server = (root->cvs_server != NULL
 			? root->cvs_server : getenv ("CVS_SERVER"));
     int i = 0;
-    /* This needs to fit "rsh", "-b", "-l", "USER", "host",
-       "cmd (w/ args)", and NULL.  We leave some room to grow. */
-    char *rsh_argv[10];
+    /* This needs to fit "rsh", "-b", "-l", "USER", "-p", port,
+       "--", "host", "cvs", "-R", "server", and NULL.
+       We leave some room to grow. */
+    char *rsh_argv[16];

@@ -105,6 +106,9 @@
 	rsh_argv[i++] = argvport;
     }

+    /* Only non-option arguments from here. (CVE-2017-12836) */
+    rsh_argv[i++] = "--";
+
     rsh_argv[i++] = root->hostname;
     rsh_argv[i++] = cvs_server;
     if (readonlyfs)
@@ -189,6 +193,8 @@
 		*p++ = argvport;
 	}

+	*p++ = "--";
+
 	*p++ = root->hostname;
 	*p++ = command;
 	*p++ = NULL;